After completing a PhD in Immunology at Trinity College Dublin, I moved to Imperial College London to study how persistent infection with a virus causes Leukemia, Lymphoma and other diseases. The virus in question is Human T cell leukemia virus type-1 (HTLV-1), which infects the very cells which defend us against viruses: T cells. Around 5% of virus-carriers develop aggressive blood cancer (Adult T cell leukemia/lymphoma, ATL), in which one infected T cell becomes malignant. ATL is very difficult to treat, and people with the most aggressive forms survive for less than a year. I made the game-changing discovery that ATL-like T cells circulate in the blood of carriers who go on to develop ATL years before they show symptoms of ATL. I am now developing new diagnostics which can detect ATL early, and together with clinicians at the U.K. National Centre for Human Retrovirology and the Memorial Sloan Kettering Cancer Centre, will test whether a recently licenced drug can eliminate ATL-like T cells in high-risk carriers.